The present invention relates to adjustable chairs, and more particularly to a molded split sleeve bushing for a gas cylinder chair seat support mechanism securing the chair seat to the chair base.
The chair design industry has heretofore provided a wide variety of chairs for the office environment which are ergonomically designed for the comfort of the user. These chairs include various adjustment mechanisms to accommodate the particular needs of the users. Adjustable chairs may, for example, include seat height adjustment mechanisms for raising and lowering the seat height relative to the base of the chair to accommodate anatomical variations of different users. Some height adjustment mechanisms employ a screw type drive for altering the height of the chair seat, while other adjustment mechanisms include a ratchet type mechanism or gas cylinder to raise and lower the chair seat.
A common problem with available height adjustable chairs is that they tend to wobble or feel loose. Typically, the chair seat support post, which may include a threaded surface for the screw type drive, is mounted to a metal or wooden base. The support post is usually metal and after a period of time the support post receptacle in the wooden base supporting the metal post wears and enlarges. Consequently, the metal post is not firmly secured within the wooden base and wobbles slightly when users sit in the chair or shift positions on the chair seat.
Similarly, metal or molded chair base assemblies develop excessive wear and unwanted movement or play between the support post and the base. Cumulative tolerances on the width and thickness of the metal components, paint coat thickness and tolerances of the molded plastic components all combine to create objectionable rattle and play in the final assembly. It is difficult to maintain a tight fit between a metal-to-metal or metal-to-plastic interface. Metal components typically include rough surfaces and sharp edges which quickly wear at the metal or metal-to-plastic interface resulting in a loose and wobbling support post for the chair seat.
A need exists for a multi-position height adjustable chair, which permits a wide latitude in vertical positioning, which is relatively easily manufactured, which is reliable in operation and which provides a wide variety of adjustable positions for the user.
It is, therefore, an object of the invention to provide a substantially wobble-free, multi-position height adjustable chair.
It is another object of the invention to provide a height adjustable chair in which the height adjustment mechanism utilizes a gas cylinder support post for height adjustment.
It is a further object of the invention to provide a height adjustable chair which minimizes wobble by reducing the tolerances between the gas cylinder support post and the chair base.
It is a further object of the invention to provide a height adjustable chair utilizing a molded split sleeve bushing for eliminating draft angle problems in the support post receptacle by providing a split sleeve bushing which seats in the draft angle of the chair base support post receptacle, providing a tight fit and smooth surface on which the gas cylinder may ride.